Warner Brothers has begun offering “app editions” of movies for iOS. Here’s the idea: Instead of paying for a movie from iTunes, you can get the app edition from… iTunes, but along with the movie you get extras including scene selection, photos, videos, trivia, and sound clips/ there’s also a “share” area where you can see Twitter updates from WB, if that’s your sort of thing.

To start, WB is offering two titles: The Dark Knight and Inception. Both apps are available as free downloads, but you’ll only be able to stream a 5 minute preview of the movie and access selected extras with the free app. You can buy full versions through in-app purchases, with The Dark Knight running $9.99 and Inception going for $11.99.

Once you’ve purchased a film you can download the entire title or stream it over the internet.

Overall, App Edition movies feel a lot like the iPhone/iPad answer to DVDs. Remember when director commentary and deleted scenes felt special? But I have to wonder how many people are going to want to pay for a movie that can only be watched on a mobile device. If you buy the same title through the iTunes media store, you can watch on a PC, Apple TV, iPhone, iPad, or other device.